Luchi del Mar might be a person known within a specific community or among her followers on Instagram. The fact that she's in a black dress on her IG story could be part of her personal style update, perhaps for an event she attended or just to show off a new look. However, without further information, it's just speculation.
One possible moral could be about the power of friendship. The witch and the crow might show that different beings can support each other in various situations, no matter how different they are.
Maybe the black dress she's wearing is a designer piece, which makes it special. Or perhaps the way she posed in the IG story while wearing it is unique.
The main characters are surely the bruja (witch) and the crow. The bruja might be depicted as having certain powers or characteristics typical of witches in folklore, such as being able to cast spells or having a connection with the supernatural. The crow, on the other hand, could play different roles. It could be a messenger for the bruja, or it could be a creature that the bruja is trying to either help or control. There could also be a relationship where the crow is the only friend of the bruja in a world that might be otherwise hostile to her.
Since I'm not familiar with this 'la bruja and the crow bed time story', it's difficult to provide the full story. However, generally, a bedtime story often has elements like interesting characters, a setting, and a plot. In this case, it seems to involve a witch (la bruja) and a crow. It might be about their adventures or some kind of relationship. But without more information, that's just speculation.